The influence of maternal energy status during mid-gestation on growth, cattle performance, and the immune response in the resultant beef progeny1

The objective of this experiment was to determine the effects of cow energy status during mid-gestation on progeny growth performance and health. To alter maternal energy status, cows (n = 151) were either fed to achieve or maintain BCS 5.0 to 5.5 (positive energy status) or fed at 80% of the energy requirements for BW maintenance (negative energy status) over the ensuing 91-d period of mid-gestation. Cows were managed as a common group beginning with the third trimester of gestation through subsequent weaning. Weaned calves (n = 71 steers and 61 heifers) were allotted to pens according to cow energy status during gestation and sex and stratified by BW to allow for live cattle performance evaluation. A subsample (n = 30) of calves was subjected to an ovalbumin challenge 19 d after entering the feedlot to compare antibody titer response. Mid-gestation dam energy status did not affect (P > 0.05) birth weight, weaning weight, or adjusted 205-d weaning weight of progeny. No differences (P > 0.05) were observed between treatments during the feeding period on ADG, DMI, and G:F. Ovalbumin results showed no interactions (P > 0.05) between treatments, days, or sexes, as well as no sex main effects. However, progeny of negative energy status cows had lower (P < 0.05) antibody titers in response to the ovalbumin challenge during the receiving period. These results suggest that differences in cow energy status applied during mid-gestation in this experiment will not affect BW or growth performance differences throughout the postnatal period in beef cattle progeny but may have an effect on the adaptive immune response during their receiving period in calves.